1. Field of the Invention
The present invention relates to a herbicidal foam composition, particularly an emulsion foam composition, having fine bubbles and fluidity.
2. Description of the Prior Art
Conventional herbicides may be classified into solid-and liquid-formulations. Each type has both advantages and disadvantages. Granules, powders, plates, and sticks are applied as solids. Water soluble powders, emulsifiable concentrates, wettable powders, concentrated solutions, flowable formulations and AL-agents (already diluted to a concentration suitable for use) are applied in liquid-formulations. Aerosol herbicidal compositions have also been developed. For example, a liquid herbicidal composition comprising a certain organic herbicide and a propellant is described in Japanese Patent Public Disclosure No. 49-101539.
As mentioned above, all conventional solid and liquid herbicidal compositions such as granules, powders, plates, sticks, aqueous solutions, emulsions, hydrates, solutions, flowable agents and AL-agents, have both advantages and disadvantages, as will be explained below.
Solid herbicidal compositions, which can be applied without dilution or other preparation, are easy to use. Dosage, however, is not always clear because of the difficulty in providing exact measurements in small-scale operations such as domestic use. It is also difficult to scatter a solid herbicide uniformly.
Most liquid herbicides have the advantage that they can be sprinkled uniformly with a watering can. They are prepared in concentrated form and must be diluted before use. This dilution sometimes causes the dosage to be unexact and prevents proper application in small-scale operations such as domestic use. Also, it is necessary to rinse out the apparatus or containers after use. Liquid herbicides used for the treatment of stems and leaves have another disadvantage in that a large portion of the sprinkled solution flows down to the ground resulting in a great waste of the active agent.
Aerosols are very convenient and require no dilution or rinsing. A large portion of sprayed aerosol, however, also flows down to the ground resulting in a great waste of the active agent. This fact also causes difficulty in visually determining which areas have been treated. Since sprayed particles are small and easily scattered, valuable plants may be damaged and humans and animals, especially the user, may be exposed to harmful inhalation of the active ingredients of the herbicide.
Thus a proper form of administration of herbicides has been desired for small-scale operations such as domestic use.
Herbicidal foam compositions are known. However, conventional foam herbicides have problems, both in volatility, viscosity, fluidity, compatibility and water-solubility of the liquid before being confined in an aerosol-container equipped with a propelling apparatus (hereinafter referred to as "the original liquid"), and in retention time of the foam, leaf depositing properties and herbicidal effects after forming a foam.